Wood-turning lathe clamp



Oct. 28, 1947. v GWATK|N WOOD-TURNING LATHE CLAMP Filed Ma'y 20, 194e Patented ct. 28,1947J UNITED STATES FATENT OFFICE 2,429,879 Woon-TURNING LATHE CLAMP valentine .Gwatkia saint vital, Manitoba, Canada Application May 20, 1946, Serial No. 670,960

(o1. are-110,)

whereby wooden or plastic plates, `bowls, picture frames and Vthe like :be held for rotation by a clamping action at spaced points upon the rims thereof and with the dnished interior of v'the article .facing towards the lathe head-stock whereby an annular :bead or flange mayY be formed con*- centrically upon the under side of the article similar to the 4bead or a-nge underneath china plates, dishes andthe like.

With the foregoing objects in View, and such other objects vand advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, my invention consists essentially in the arrangement and construction of parts all .as hereinafter more particularly described, reference being had .to the accompanying drawings, in which:

Figure l is an elevation of my clamp viewed from the headstock side or `the lathe to which it is intended to be attached.-

Figure 2 is a smaller view similar to Figure l and including a representation of my clam-p tightening and slackening tool thereon.

Figure 3 is a reduced vfragmentary cross-sect-ionas viewed in .the direction -of arrows 3-3 in Figure 1. l

Figure 4 isa cross-sectional representation of a wooden bowl showing 'the annular bead upon the under side thereof, the formation of which is rendered possible by the .useof my clamp.

Figure 5 is a fragmentary representation of one of the clamping elements by which the ri-m of `a piece of work is held during the formation of the aforementioned 'bead or annular underside-y flange.

In the drawings like `characters of reference indicate corresponding parts in the diii'erent figures.

Hitherto wood-turners engaged in the making of bowls, plates and the like such as that illustrated in the accompanying Figure 4 have been unable to provide an annular bead or flan-ge I upon the undersurface 2 thereof ydue to the impossibility of turning the article around from the position illustrated so that the interior surface 3 is facing the headstock of an associated lathe, and which, as is well known, is positioned to the left of the operator facing such lathe.

The practice commonly adopted in the manufacture of an article such as that illustrated in a block of Wood at three or more points to the headstock and substantially conliplfetizng the man.-

uf-acture of the article While thus held. This 'leaves a concentric boss 4 upon the underside of the article into which the securing screws enter, and upon removal vof the otherwise finished article, the boss 'is removedto provide a central undersurface such as that designated by the line vEs, and the short phantom `lines 6.

By the use of my clamp however, I am able, when the interior of the article is finished, and a perimeter Tl has been formed, to turn the work around so that the interior surface faces the headstock, and secure the same by means of the .device hereinafter to be described. Then, :if the undersurface has not been finished, I am .able t0 it while standing in the same position as that adopted when working on the interior surface, and am able to chisel down .the boss 4, and form from it, the aforesaid annular bead i whereby the appearance of the finished article is enhanced.

The device by means .of which the aforesaid reversal of a partly nished bowl, plate lor the like is effected comprises a pair of co-axially positioned, .adjacent plates .f8 and 9, the former of which I designate as .a Work facing plate, and the latter as a headstock plate. The Work facing plate is provided with the sleeve ID, the left hand end of such sleeve being intended for .attachment to .the lathe headstock. Upon the sleeve is an annular shoulder Il, headstock plate 9 beingr journalled on the sleeve I' and so freely rotatable. As clearly illustrated Ain Figure 3 plate 9 abuts the flank `.of the shoulder Il being held in place by the retaining band l2 secured within groove |13 provided therefor. The .sleeve I0 is preferably internally screw-threaded as at 1M so that it may be engaged 'by a mandrel or arbor associated with the lathe headstock. Also formed upon the .sleeve lill and normal to the rotary axis thereof are apertures I5 for .the purpose hereinafter specified..

Pivotally vconnected at the .spaced intervals indicated by 'numerals 1'6 to plate .9 A'adjacent the perimeter thereof, .and lying against the interior .surface are radiating arms `I'I, the outer ends I8 whereof are freely connected to the outer ends of an .equivale-nt number of arms I9 pivotally connected at the inner ends 20 thereof to the face plate 8 at the positions indicated and overlapping or lying against the outer surface of the said face plate.

Also freely secured as at 2l to face plate 8, but against the interior surface thereof are radially disposed and longitudinally slotted bars 22. Through the slots 23 of these bars project the 3 nut and bolt assemblies 24 which are secured to the arms I9 approximately mld-way of their length. The nut and bolt assemblies are tightenable against the bars 22.

From the foregoing it will be recognized that plates 8 and 9 may be rotated independently of each other, and by rotation it will be obvious that the united ends of each pair of arms I1 and I9 may be moved towards or away from the clamp axis 25. Adjacent the united end of each pair of arms I'l and I9, and secured against the exterior surfaces of the arms I9 are clamping elements in the form of hooked pieces of flat stock, and which, it will be clearly understood, are intended to engage the outer perimeter 'I of such a piece of work as that designated in Figure 4 when facing the opposite way to that illustrated.

When thus clamped it will clearly be recognised that I am able to work upon the under surface of an article in process of manufacture, and while engaged in tooling such under surface I am able at intervals to examine the inner surface which is facing towards the facing plate 8 of my clamp since large areas of the interior will be clearly viewable as indicated by reference to the perimeter I which I have indicated by a phantom line in Figure 1. This is desirable to obviate the possibility of the .article being tooled down to an excessive thinness.

In association with the clamp which I have now described I employ the tool collectively designated 21 and which consists of the angulated bar 28, the end of the arm 29 whereof is intended to enter any of the several apertures I5. Adjacent the locus of angulation of the bar 28 and projecting upon the interior side thereof is a lever 3e secured to the bar 28 via the strap 3l. Pivotally secured to the outer end of the lever 3l! is a link 32 the remaining end whereof is hooked as at 33 whereby the links may be anchored to projections 34 or 34' projecting from the exterior surface of the headstock plate S.

By this means it Will be apparent that, by grasping with one hand, the acutely angulated lever and arm 35 of bar 28, and squeezing, I am able to rotate lever 30 towards arm 35 and carry with it the link 32 whereby plate 9 is rotated relative to plate 8 clockwise or counter- Aclockwise to move the clamping element 23 radially inwardly or outwardly.

Thus, with respect to Figure 2 it will readily be apprehended that a squeezing action upon lever 39 will move the same clockwise as indicated by arrow 36 about the pivot point 3l so that plate 9 is also moved clockwise to pull arms Il around with it thereby moving the clamping element 26 inwardly and increasing the angle between each pair of arms I1 and I9. However, when the tool 21 is turned around so that hook 33 is engaged with stud 34' obviously a similar squeezing action will rotate plate 9 in a counterclockwise direction so that the angle between each pair of arms grows more acute whereby the elements 26 are moved outwardly and the piece of work becomes unclamped.

Finally it is to be noted that between the various nut and bolt assemblies such as 24, and those which connect each pair of arms I1 and I9 at the outer ends I8 thereof, I provide spacers in the form of collars or a plurality of washers to provide for the thickness of plate 8.

Since various modifications can be made in my invention as hereinabove described and many apparently widely different embodiments of same made within the scope of the claims without departing from such spirit and scope, it is intended `that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense and I desire only such limitations placed thereon as are specifically expressed in the accompanying claims.

What I claim as my invention is:

1. A wood-turners .clamp for the purpose herein specified and attachable to the headstock of a wood-turning lathe, said clamp consisting of a pair of adjacent plates mutually connected for independent coaxial rotation, the plate attached to said headstock being designated as a headstock plate, and the other as the work facing plate, a plurality of radiating arms pivotally connected to said headstock plate and an equivalent number on said facing plate, each arm on the former being pivotally Iconnected to a different one of the arms on the latter at a point beyond the perimeter of said plates, work clamping elements on each of the pairs of arms so connected, and means for maintaining said plates in any one of a desired plurality of rotary relationships.

2. A wood-turners clamp for the purpose herein specified and attachable to the headstock of a wood-turning lathe, said clamp consisting of a pair of adjacent plates mutually connected for independent coaxial rotation, the plate attached to said headstock being designated as a headstock plate, and the other as the work facing plate, a plurality of radiating arms pivotally connected to said headstock plate and an equivalent number on said facing plate, each arm on the former being pivotally connected to a differentY one of the arms on the latter at a point beyond the perimeter of said plates, work clamping elements on each of the pairs of arms so connected, and at least one longitudinally slotted bar attached to one of said plates and projecting therefrom together with a locking assembly secured to said bar and also to one of the other bars of said clamp, said locking assembly extending through said slot and being frictionally engageable with said bar adjacent to said slot at any desired point on the length of said slot for the purpose of maintaining said plates in any one of desired plurality of rotary relationships.

. VALENTINE GWA'IKIN.

REFERENCES CITED Y The following references are of record in the file of this patent:

UNITED STATES PATENTS 

